Identification of susceptibility determinants in the tomato- Clavibacter michiganensis pathosystem

Abstract

Chapters 4 and 5 aimed at the identification and functional characterization of candidate S genes. Using post-transcriptional silencing through virus-induced gene silencing (VIGS), we selected three candidate genes (SlWRKY23, and the putative oxygenases Solyc09g089680.3 and Solyc12g005380.2) for further analysis. For these genes, we generated mutants using CRISPR/Cas9 and studied potential changes in susceptibility and bacterial dynamics of Cm in the mutants.In Chapter 6, we set out to identify the genes underlying tolerance on the major QTL on chromosome 7 observed in a previously described cross between the accession S. arcanum LA2157 and S. lycopersicum. To our surprise, the QTL on chromosome 7 that was previously found to result in high tolerance to Cm, did not co-segregate with our observed tolerant phenotypes. Therefore, we employed a bulk segregant analysis (BSA) to identify the causal loci. This thesis is concluded with Chapter 7, in which I summarize and discuss the implications of our main findings in achieving resistance to Cm. Finally, I finish the discussion with questions about the molecular aspects of the interaction that remain to be answered.